Featured bullnose ramp for a thrust reverser system

Abstract

An assembly is provided for an aircraft propulsion system. This assembly includes a forward thrust duct and a thrust reverser system. The thrust reverser system includes a thrust reverser duct, a bullnose ramp and a plurality of protrusions. The bullnose ramp is adapted to provide a transition from the forward thrust duct to the thrust reverser duct when the thrust reverser system is in a deployed configuration. The protrusions are bonded or formed integral with the bullnose ramp. Each of the protrusions is adapted to interact with boundary layer fluid flowing along the bullnose ramp from the forward thrust duct into the thrust reverser duct when the thrust reverser system is in a deployed configuration.

What is claimed is: 
     
       1. An assembly for an aircraft propulsion system, comprising:
 a forward thrust duct; and 
 a thrust reverser system comprising a thrust reverser duct, a bullnose ramp, a plurality of protrusions and a cascade; 
 the bullnose ramp adapted to provide a transition from the forward thrust duct to the thrust reverser duct when the thrust reverser system is in a deployed configuration; and 
 the plurality of protrusions bonded or formed integral with the bullnose ramp, each of the plurality of protrusions adapted to interact with boundary layer fluid flowing along an upstream portion of the bullnose ramp from the forward thrust duct into the thrust reverser duct when the thrust reverser system is in the deployed configuration; 
 the cascade comprising a plurality of flow channels, a first of the plurality of flow channels circumferentially adjacent a second of the plurality of flow channels; 
 a first of the plurality of protrusions circumferentially aligned with the first of the plurality of flow channels, a second of the plurality of protrusions is circumferentially aligned with the second of the plurality of flow channels, and the second of the plurality of protrusions is circumferentially adjacent the first of the plurality of protrusions; 
 a third of the plurality of protrusions circumferentially aligned with the second of the plurality of flow channels, and the third of the plurality of protrusions circumferentially adjacent the second of the plurality of protrusions; and 
 a first circumferential distance between the first of the plurality of protrusions and the second of the plurality of protrusions greater than a second circumferential distance between the second of the plurality of protrusions and the third of the plurality of protrusions, the first circumferential distance decreasing as the first of the plurality of protrusions extends axially towards the first of the plurality of flow channels, and the second circumferential distance increasing as the second of the plurality of protrusions extends axially towards the second of the plurality of flow channels. 
 
     
     
       2. The assembly of  claim 1 , wherein at least one of the plurality of protrusions comprises a vortex generator. 
     
     
       3. The assembly of  claim 1 , wherein at least one of the plurality of protrusions projects out from the bullnose ramp into an inlet to the thrust reverser duct. 
     
     
       4. The assembly of  claim 1 , wherein a chord line of the first of the plurality of protrusions is parallel with a chord line of the second of the plurality of protrusions. 
     
     
       5. The assembly of  claim 1 , wherein a chord line of the first of the plurality of protrusions is angularly offset from a chord line of the second of the plurality of protrusions. 
     
     
       6. The assembly of  claim 1 , wherein at least one of the plurality of protrusions has a planar geometry. 
     
     
       7. The assembly of  claim 1 , wherein at least one of the plurality of protrusions has a non-planar geometry. 
     
     
       8. The assembly of  claim 1 , wherein
 the first of the plurality of protrusions extends longitudinally from an upstream end to a downstream end; and 
 a height of the first of the plurality of protrusions at the upstream end is different than the height of the first of the plurality of protrusions at the downstream end. 
 
     
     
       9. The assembly of  claim 1 , wherein
 the first of the plurality of protrusions extends longitudinally from an upstream end to a downstream end; and 
 a height of the first of the plurality of protrusions at the upstream end is equal to the height of the first of the plurality of protrusions at the downstream end. 
 
     
     
       10. The assembly of  claim 1 , wherein
 the bullnose ramp extends circumferentially about an axial centerline; and 
 the first of the plurality of protrusions is axially aligned with the second of the plurality of protrusions. 
 
     
     
       11. The assembly of  claim 1 , wherein
 the bullnose ramp extends circumferentially about an axial centerline; and 
 the first of the plurality of protrusions is axially offset from the second of the plurality of protrusions. 
 
     
     
       12. The assembly of  claim 11 , wherein a size of the first of the plurality of protrusions is different than a size of the second of the plurality of protrusions. 
     
     
       13. The assembly of  claim 1 , wherein the bullnose ramp forms an upstream boundary of an inlet to the thrust reverser duct when the thrust reverser system is in the deployed configuration. 
     
     
       14. The assembly of  claim 1 , wherein
 the bullnose ramp extends circumferentially about an axial centerline; and 
 the bullnose ramp has a surface with an arcuate sectional geometry when viewed in a plane parallel with the axial centerline. 
 
     
     
       15. The assembly of  claim 1 , wherein
 the aircraft propulsion system comprises a turbofan aircraft propulsion system; and 
 the forward thrust duct comprises a bypass duct. 
 
     
     
       16. The assembly of  claim 1 , wherein
 the thrust reverser system further comprises a moveable component; 
 a channel is formed by and between the bullnose ramp and an upstream edge of the moveable component when the thrust reverser system is in a stowed configuration; and 
 at least one of the protrusions is arranged within the channel. 
 
     
     
       17. The assembly of  claim 1 , wherein the thrust reverser system further comprises a moveable component; the moveable component axially abuts the bullnose ramp when the thrust reverser system is in a stowed configuration; and at least one of the protrusions is axially overlapped by and radially outboard of the moveable component when the thrust reverser system is in the stowed configuration.